package edu.swjtu.servlet;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.patchca.background.BackgroundFactory;
import org.patchca.color.ColorFactory;
import org.patchca.color.RandomColorFactory;
import org.patchca.filter.ConfigurableFilterFactory;
import org.patchca.filter.library.AbstractImageOp;
import org.patchca.filter.library.WobbleImageOp;
import org.patchca.font.RandomFontFactory;
import org.patchca.service.Captcha;
import org.patchca.service.ConfigurableCaptchaService;
import org.patchca.text.renderer.BestFitTextRenderer;
import org.patchca.text.renderer.TextRenderer;
import org.patchca.word.RandomWordFactory;

public class ValidationCodeServlet extends HttpServlet {
	private static final long serialVersionUID = 5126616339795936447L;  
    private ConfigurableCaptchaService configurableCaptchaService = null;  
    private ColorFactory colorFactory = null;  
    private RandomFontFactory fontFactory = null;  
    private RandomWordFactory wordFactory = null;  
    private TextRenderer textRenderer = null;  
    
    public ValidationCodeServlet() {  
        super();  
    }  
    /** 
     * Servlet销毁方法,负责销毁所使用资源. <br> 
     */  
    public void destroy() {  
        wordFactory = null;  
        colorFactory = null;  
        fontFactory = null;  
        textRenderer = null;  
        configurableCaptchaService = null;  
        super.destroy(); // Just puts "destroy" string in log  
    }  
    public void doGet(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  
        doPost(request, response);  
    }  
    public void doPost(HttpServletRequest request, HttpServletResponse response)  

            throws ServletException, IOException {  

        response.setContentType("image/png");  

        response.setHeader("cache", "no-cache");  
        HttpSession session = request.getSession(true);  
        OutputStream outputStream = response.getOutputStream();  
        // 得到验证码对象,有验证码图片和验证码字符串  
        Captcha captcha = configurableCaptchaService.getCaptcha();  
        // 取得验证码字符串放入Session  
        String validationCode = captcha.getChallenge();  
        session.setAttribute("validationCode", validationCode);  
        // 取得验证码图片并输出  
        BufferedImage bufferedImage = captcha.getImage();  
        ImageIO.write(bufferedImage, "png", outputStream);  
        outputStream.flush();  
        outputStream.close();  
    }  
    /** 
     * Servlet初始化方法 
     */  
    public void init() throws ServletException {  
        configurableCaptchaService = new ConfigurableCaptchaService();  
        // 颜色创建工厂,使用一定范围内的随机色  
        colorFactory = new RandomColorFactory();  
        configurableCaptchaService.setColorFactory(colorFactory);  
        // 随机字体生成器  
        fontFactory = new RandomFontFactory();  
        fontFactory.setMaxSize(32);  
        fontFactory.setMinSize(28);  
        configurableCaptchaService.setFontFactory(fontFactory);  
        // 随机字符生成器,去除掉容易混淆的字母和数字,如o和0等  
        wordFactory = new RandomWordFactory();  
        wordFactory.setCharacters("abcdefghkmnpqstwxyz123456789");  
        wordFactory.setMaxLength(5);  
        wordFactory.setMinLength(4);  
        configurableCaptchaService.setWordFactory(wordFactory);  
        // 自定义验证码图片背景  
        MyCustomBackgroundFactory backgroundFactory = new MyCustomBackgroundFactory();  
        configurableCaptchaService.setBackgroundFactory(backgroundFactory);  
        // 图片滤镜设置  
        ConfigurableFilterFactory filterFactory = new ConfigurableFilterFactory();  
        List<BufferedImageOp> filters = new ArrayList<BufferedImageOp>();  
        WobbleImageOp wobbleImageOp = new WobbleImageOp();  
        wobbleImageOp.setEdgeMode(AbstractImageOp.EDGE_MIRROR);  
        wobbleImageOp.setxAmplitude(2.0);  
        wobbleImageOp.setyAmplitude(1.0);  
        filters.add(wobbleImageOp);  
        filterFactory.setFilters(filters);  
        configurableCaptchaService.setFilterFactory(filterFactory);  
        // 文字渲染器设置  
        textRenderer = new BestFitTextRenderer();  
        textRenderer.setBottomMargin(3);  
        textRenderer.setTopMargin(3);  
        configurableCaptchaService.setTextRenderer(textRenderer);  
        // 验证码图片的大小  
        configurableCaptchaService.setWidth(70);  
        configurableCaptchaService.setHeight(25);  
    }  
    /** 
     * 自定义验证码图片背景,主要画一些噪点和干扰线 
     */  
    private class MyCustomBackgroundFactory implements BackgroundFactory {  
        private Random random = new Random();  
        public void fillBackground(BufferedImage image) {  
            Graphics graphics = image.getGraphics();  
            // 验证码图片的宽高  
            int imgWidth = image.getWidth();  
            int imgHeight = image.getHeight();  
            // 填充为白色背景  
            graphics.setColor(Color.LIGHT_GRAY);  
            graphics.fillRect(0, 0, imgWidth, imgHeight);  
            // 画100个噪点(颜色及位置随机)  
            for(int i = 0; i < 100; i++) {  
                // 随机颜色  
                int rInt = random.nextInt(255);  
                int gInt = random.nextInt(255);  
                int bInt = random.nextInt(255);  
                graphics.setColor(new Color(rInt, gInt, bInt));  
                // 随机位置  
                int xInt = random.nextInt(imgWidth - 3);  
                int yInt = random.nextInt(imgHeight - 2);  
                // 随机旋转角度  
                int sAngleInt = random.nextInt(360);  
                int eAngleInt = random.nextInt(360);  
                // 随机大小  
                int wInt = random.nextInt(6);  
                int hInt = random.nextInt(6);  
                graphics.fillArc(xInt, yInt, wInt, hInt, sAngleInt, eAngleInt);  
                // 画5条干扰线  
                if (i % 20 == 0) {  
                    int xInt2 = random.nextInt(imgWidth);  
                    int yInt2 = random.nextInt(imgHeight);  
                    graphics.drawLine(xInt, yInt, xInt2, yInt2);  
                }  
            }  
        }  
    }  
}  
